This study evaluated the efficacy of daily brain-machine-interface (BMI) training in chronic stroke patients with severe hand weakness, comparing it to physiotherapy alone. Thirty-two patients were randomly assigned to two groups: an experimental group that received BMI training and a control group that received sham-BMI training. Both groups also received identical behavioral physiotherapy. The primary outcome measure was the combined hand and arm scores (motor part) from the modified upper limb Fugl-Meyer Assessment (cFMA). The experimental group showed a significant improvement in cFMA scores, reflecting a clinically meaningful change from no activity to some in paretic muscles. This improvement was correlated with changes in functional MRI laterality index and paretic hand electromyography activity. Placebo-expectancy scores were comparable between the two groups. The study concluded that the addition of BMI training to behaviorally oriented physiotherapy can induce functional improvements in motor function in chronic stroke patients without residual finger movements, potentially opening new avenues in stroke neurorehabilitation.This study evaluated the efficacy of daily brain-machine-interface (BMI) training in chronic stroke patients with severe hand weakness, comparing it to physiotherapy alone. Thirty-two patients were randomly assigned to two groups: an experimental group that received BMI training and a control group that received sham-BMI training. Both groups also received identical behavioral physiotherapy. The primary outcome measure was the combined hand and arm scores (motor part) from the modified upper limb Fugl-Meyer Assessment (cFMA). The experimental group showed a significant improvement in cFMA scores, reflecting a clinically meaningful change from no activity to some in paretic muscles. This improvement was correlated with changes in functional MRI laterality index and paretic hand electromyography activity. Placebo-expectancy scores were comparable between the two groups. The study concluded that the addition of BMI training to behaviorally oriented physiotherapy can induce functional improvements in motor function in chronic stroke patients without residual finger movements, potentially opening new avenues in stroke neurorehabilitation.